Background: '86 Z28 carb'd w/ T5. Stock oil press and water temp gauges broken and tach not accurate. Installed mechanical o/p and w/t gauges.
Now, I've swapped in an entire '92 305 TPI engine w/ harness forward of firewall and ecm. I'm replacing all remaining gauges (Tach, Mechanical speedo, fuel level), and want to wire back in the "idiot" check engine light. AIR and cats have been removed (it's a roadrace car), ERG and charcoal canister remain. Car is still being built, not running yet.

Questions:
1. Does the computer require any signal from the VSS?
I've read that it has something to do w/ locking the torque converter and cruise control, neither of which I have. Also, I've read that it will throw a code. As of now, the original cable drive is installed, the wiring for the VSS is tucked out of the way.

2. Does the computer get any signal from the w/t and o/p senders?
If not, I guess I can just replace the factory senders w/ the ones from the gauges. If it does get a signal, where can I plug in the aftermarket senders?

My goal is to retain the ability to pull still be able to pull diagnostic codes from the check engine light.